A8483
Package EK:
MLP/TDFN, 3 × 3 mm
0.75 mm Nominal Height
1.2 MHz Step-up Converter
for Display Bias Supply
The A8483 is a current mode step-up dc-to-dc converter,
available in a 5-pin 3 mm × 3 mm thermally enhanced
MLP/TDFN lead (Pb) free package. Smaller external
components and integrated 36 V switch reduce component
count and footprint for a variety of applications.
APPLICATIONS
OLED bias supply / WLED backlight
Portable battery-powered equipment
Cellular phones
PDAs (Personal Digital Assistant)
Camcorders, personal stereos, MP3 players, cameras
Mobile GPS systems
Approximate Scale 1:1
FEATURES
Output voltage up to 35 V
2.5 to 10 V input
0.9 to 18 V input with separate bias supply
Delivers 15 V at 15 mA with 2.7 V input
Constant 1.2 MHz switching frequency provides low noise
350 mA switch current limit
1
μA
shutdown current
Low-noise PWM/analog dimming
V
OUT
5
VIN
V
SUPPLY
C1
1 µF
EN
4
Enable
R2
39 kΩ
L1
10 µH
1
SW
D1
I
OUT1
+ I
OUT2
= 15 mA
5
VIN
L1
10 µH
1
SW
D1
R1
732 kΩ
FB
3
V
OUT2
R2
39 kΩ
D2
–12 V
V
OUT1
+12 V
OLED
A8483
GND
2
FB
3
R1
820 kΩ
C2
1µ
µF
V
SUPPLY
C1
1 µF
EN
4
Enable
A8483
GND
2
C2
0.47 µF
C3
0.47 µF
Li-ion
2.5 V to
5.5 V
Li-ion
2.5 V to
5.5 V
C4
0.47 µF
Figure 1.
OLED Bias Supply.
Use for cell phones, MP3
players, DSCs, and PDAs.
32 V, 18 mA
V
OUT
5
VIN
V
SUPPLY
C1
1 µF
5V
EN
4
Enable
R2
15 kΩ
L1
10 µH
1
SW
D1
R1
768 kΩ
for
V
OUT
=
32 V
604 kΩ
for
V
OUT
=
25 V
25 V, 25 mA
Figure 2.
Small LCD Bias Supply.
Li+ battery to ±12 V.
Connect either V
Z
or V
BIAS
V
Z
7.5 V
L1
22 µH
1
SW
D1
R1
768 kΩ
for
V
OUT
=
32 V
604 kΩ
for
V
OUT
=
25 V
R2
15 kΩ
V
OUT
32 V, 40 mA
25 V, 80 mA
A8483
GND
2
FB
3
C2
1 µ / 50 V
µF
V
SUPPLY
12 V
C1
1 µF
V
BIAS
5V
5
VIN
EN
4
Enable
A8483
GND
2
FB
3
C2
1 µ / 50 V
µF
C3
0.1 µF
Figure 3.
LCD TV, Plasma TV Bias, FED Display,
Varactor Diode Bias.
Using 5 V input.
V
OUT
5
VIN
V
SUPPLY
C1
1 µF
EN
4
Enable
Cf
0.01 µF
L1
10 µH
1
SW
D1
C2
0.22 µF
V
C
Analog Voltage or
PWM
R1
47
Ω
Figure 4.
LCD TV, Plasma TV Bias, FED Display,
Varactor Diode Bias.
Using 12 V input.
V
OUT
5
VIN
L1
10 µH
1
SW
D1
R1
560 kΩ
FB
3
R3
160 kΩ
R2
47 kΩ
Cf
1 nF
C2
1 µF
OLED
Cf for PWM dimming only
V
C
A8483
GND
2
FB
3
R2
5 kΩ
R3
24 kΩ
V
SUPPLY
Li-ion
2.5 V to
5.5 V
C1
1 µF
EN
4
Enable
A8483
GND
2
Li-ion
2.5 V to
5.5 V
Figure 5.
WLED Backlighting.
A8483-DS, Rev. 1
Analog Voltage or
PWM 10 kHz
Figure 6.
OLED Bias Supply.
Use for low-noise PWM
dimming, or with analog voltage through the FB pin.
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
